Modular force-measuring cell for a weighing scale, and weighing scale

Abstract

A modular force-measuring cell is disclosed which includes a force transducer equipped with sensors that measure changes occurring in the state of the force transducer as a result of a force or temperature. The force-measuring cell also includes a memory module for storing compensation data associated with the modular force-measuring cell. The memory module and at least one converter circuit for the conversion of the signals delivered by the sensors are arranged in a circuit module that is mechanically and thermally coupled to the force transducer.

1. A modular force-measuring cell comprising:
 a force transducer equipped with sensors that measure changes of the force transducer as a result of a force or temperature; 
 a memory module for storing compensation data associated with the modular force-measuring cell; and 
 a circuit module mechanically and thermally coupled to the force transducer, wherein said circuit module comprises the memory module, at least one converter circuit for converting analog signals delivered by the sensors, and a connector terminal arrangement through which the memory module and the converter circuit each are connectable separately to a processor module, wherein the processor module is spatially set apart from the force-measuring cell to provide a thermal uncoupling between the processor module and the force measuring cell. 
 
   
   
     2. The modular force-measuring cell according to  claim 1 , wherein in addition to the memory module, the circuit module comprises substantially only circuit components associated with analog signal processing activity that is functionally close to the sensors. 
   
   
     3. The modular force-measuring cell according to  claim 1 , comprising:
 two converter circuits for generating digital signals corresponding to analog signals delivered by the sensors representing, respectively, an applied force and a temperature of the force transducer. 
 
   
   
     4. The modular force-measuring cell according to  claim 1 , wherein the circuit module is connected by a ribbon connector to the processor module, said processor module being operable to read the compensation data from the memory module and to perform processing of the digital signals delivered by the at least one converter circuit. 
   
   
     5. The modular force-measuring cell according to  claim 1 , wherein the circuit module comprises a substrate with conductive tracks. 
   
   
     6. The modular force-measuring cell according to  claim 1 , comprising:
 a metal element which is at least partially in surface contact with a substrate of the circuit module and releasably connected to the force transducer, wherein the circuit module is configured to be connected to the metal element. 
 
   
   
     7. The modular force-measuring cell according to  claim 1 , wherein the force transducer comprises a deformable body which can be configured as a parallelogram-shaped measuring element with elastically deformable material portions carrying at least one sensor, connected by means of at least one flexible ribbon connector to the circuit module. 
   
   
     8. The modular force-measuring cell according to  claim 7 , wherein a conductive track of the flexible ribbon connector which leads to the sensor is printed on a flexible ribbon or foil material. 
   
   
     9. The modular force-measuring cell according to  claim 7 , wherein the deformable body carries four sensors connected to form a measuring bridge circuit. 
   
   
     10. The modular force-measuring cell according to  claim 9 , wherein the sensors are strain gauges. 
   
   
     11. The modular force-measuring cell according to  claim 9 , wherein conductive tracks leading to each of the sensors are printed on a flexible ribbon or foil material, and are dimensioned so that connector leads to terminals of the sensors have at least approximately equal resistance values, including cases where a connector lead consists of two or more sections. 
   
   
     12. The modular force-measuring cell according to  claim 9 , wherein the sensors are connected to the circuit module by means of at least two separately routed flexible ribbon connectors. 
   
   
     13. The modular force-measuring cell according to  claim 11 , wherein the conductive tracks leading to the sensors have partial sections that are used in common by two or more of the sensors for reducing a number of connector terminals on the circuit module. 
   
   
     14. The modular force-measuring cell according to  claim 9 , comprising:
 a temperature-probing sensor arranged at a location where a temperature level represents an average of temperatures at the sensors of the measuring bridge circuit. 
 
   
   
     15. The modular force-measuring cell according to  claim 3 , wherein the digital signals are pulse-width modulated signals. 
   
   
     16. The modular force-measuring cell according to  claim 1 , in combination with a weighing scale. 
   
   
     17. The modular force-measuring cell according to  claim 3 , wherein the circuit module is connected by a ribbon connector to the processor module, said processor module being operable to read the compensation data from the memory module and to perform processing of the digital signals delivered by at least one of the two converter circuits. 
   
   
     18. The modular force-measuring cell according to  claim 17 , comprising:
 a metal element which is at least partially in surface contact with a substrate of the circuit module and releasably connected to the force transducer, wherein the circuit module is configured to be connected to the metal element. 
 
   
   
     19. The modular force-measuring cell according to  claim 18 , wherein the force transducer comprises a deformable body which can be configured as a parallelogram-shaped measuring element with elastically deformable material portions carrying at least one sensor, connected by means of at least one flexible ribbon connector to the circuit module. 
   
   
     20. The modular force-measuring cell according to  claim 19 , wherein a conductive track of the flexible ribbon connector which leads to the sensor is printed on a flexible ribbon or foil material. 
   
   
     21. The modular force-measuring cell according to  claim 20 , comprising:
 a temperature-probing sensor arranged at a location where a temperature level represents an average of temperatures at the sensors of the measuring bridge circuit. 
 
   
   
     22. A modular force-measuring cell comprising:
 a force transducer equipped with sensors that measure changes of the force transducer as a result of a force or temperature; 
 a memory module for storing compensation data associated with the modular force-measuring cell; and 
 a circuit module mechanically and thermally coupled to the force transducer, wherein said circuit module comprises the memory module, at least one converter circuit for converting analog signals delivered by the sensors, and a connector terminal arrangement which connects the memory module and the converter circuit to a processor module, wherein the processor module is thermally uncoupled from the circuit module.